Conventionally, in a weft knitting apparatus in which a knitting needle in a needle bed is made to perform a knitting operation by a cam mechanism while a carriage runs to and fro in the longitudinal direction of the needle bed, a yarn carrier is used so as to supply knitting yarn to the knitting needle while moving in conjunction with the carriage. The yarn carrier is also referred to as a yarn feeder or a yarn guide. The yarn carrier moves along a yarn guide rail which is installed above the needle bed and parallel with the longitudinal direction of the needle bed. The carriage and the yarn carrier are linked to each other by a pin which is disposed to the carriage and capable of appearing toward the yarn carrier. The weft knitting apparatus is provided with a plurality of yarn guide rails. To one yarn guide rail, a passage for one yarn carrier or passages for a plurality of yarn carriers can be disposed. The carriage is provided with pin appearing mechanisms for a plurality of passages and capable of selecting a yarn carrier by making the pin appear.
FIG. 11 shows a simplified construction of a conventional and typical yarn carrier 51. The yarn carrier 51 is capable of running along a yarn guide rail 52, and is engaged with a pin 54 protruding from a carriage 53 and hauled. Below a casing 55 of the yarn carrier 51, a feeder rod 56 is pendent, and a yarn feeding port 57 is disposed to the tip thereof. On the upper face of the casing 55, a concave part 60 having engagement points 58, 59 to be engaged with the pin 54 on both sides thereof is formed. On both outer sides of the casing 55, guiding slopes 61, 62 are disposed. Since a cam which makes a knitting needle perform a knitting operation is substantially triangle, the two engagement points are necessary in order to make the yarn carrier 51 have a specified delay amount AL in accordance with a running direction of the carriage 53.
It is assumed that, in order to select the yarn carrier 51 stationary on the yarn guide rail 52, the carriage 53 is running toward the yarn carrier 51. The pin 54 protrudes from the carriage 53 and approaches the yarn carrier 51. The pin 54 is biased downward by a spring, and comes close to the concave part 60 while running onto the guiding slope 62. The pin 54 passes by the engagement point 59 on the rear side in the running direction, and the tip of the pin 54 abuts on the side wall face of the concave part 60 in the engagement point 58 on the front side in the running direction. After the point of time of abutting, the yarn carrier 51 is hauled by the carriage 53, thereby becoming movable. The applicant of this application has disclosed a yarn carrier provided with two engagement points in this manner in Japanese Patent Nos. 2807848, 2903152 and so on.
Since, as shown in FIG. 11, the yarn carrier 51 provided with the two engagement points 58, 59 moves in a state where the rear side thereof at the time of being hauled by the carriage 53 is not engaged with the pin 54 at all times, there is a possibility that, when the carriage 53 is suddenly stopped, the yarn carrier 51 goes ahead of the carriage 53 because of inertia. For this reason, for example, sliding resistance at the time when the yarn carrier 51 runs along the yarn guide rail 52 is set large so that, when a driving force from the pin 54 stops, the yarn carrier 51 also stops immediately. Therefore, it is necessary to transmit such a driving force that overcomes the resistance from the pin 54 to the engagement point 58 when making the yarn carrier 51 hauled.
In order to make it possible to transmit a large force from the pin 54, it is necessary to enlarge a driving force of the carriage 53. It is also necessary to strengthen and upsize an appearing mechanism of the pin 54 and so on. Abrasion of a sliding part between the yarn guide rail 52 and the yarn carrier 51 and so on also increases.
An object of the present invention is to provide a yarn carrier of a weft knitting apparatus which, even when having two engagement points, is capable of certainly engaging both sides of a pin from a carriage in the respective engagement points.